Dynamo-electric machine



EFALWATSON.

DYNAMO ELECT-BIC MACHINE. nrucmou man OCT- 24. 192:.

Patented J uly 11, 1922.

UNITED STATES WATSON, or COVENTRY, ENGLAND, ASSIGNOR TO THE M-L uaqu -r EEN EST ANSLEY PATENT OFFICE.

SYNDICATE LIMITED, OF COVENTRY, ENGLAND.

DYNAMO-ELECTRIG MACHINE.

' T all whom it may concern:

have filed an application in Great Britain,

September 25, 1920, No. 27,361), of which the following is a specification.

This invention relates to small dynamo electric machines, such as current generators and ignition magnetos, in which laminated pole pieces are mounted between end pieces. The main object of the invention is to facilltate the construction of the field systems of such machines. A further object is to provide improved means for'securing flat permanent magnets to the pole pieces.

The invention comprises the construction of each pole piece from a number of suitably shaped laminations which are held together loosely or rigidly to form a complete unit, and the location of the same by dowel or peg connections with the end pieces, the whole beingsecured by bolts or the like connecting the end'pieces. Also the invention comprises the adaptation of the pole pieces to engage between them the ends of one or more fiat permanent magnets, edgewise displacement of the magnets being prevented by the end pieces.

In the accompanying sheet of explanatory drawings Figure 1 is a side elevation of a magneto fitted with pole pieces and magnets constructed and arranged in accordance with this invention.

' Figure 2 is a cross section of the machine.

Figure 3 is a cross section illustrating an alternative construction.

In applying the invention as shown in Figures 1 and 2 to the field systems of a small electric current generator, or an ignition magneto, each pole piece a is constructed from a number of suitably shaped laminations which are held together either loosely or rigidly to form a unit, by dowels, or pegs b or by rivets, screws or the like passing laterally through them. y The dowels or pegs extend beyond the side faces of the pole pieces and the inner faces of the end pieces a of the machine are recessed to receive the dowels.

Specification of Letters Patent.

Patented July 11, 1922.

Application filed. October 24, 1921. Serial No. 510,098.

In assembling, the required number of pole pieces are engaged by means of the dowels or the like with the end pieces and the whole are secured together by two or more screws cl, bolts, or like fastenings inserted through the end pieces. Such fastenings may be situated outside or clear of the pole pieces as shown, or they may pass through the same.

\Vhen it is desired to associate one or 'more flat or short bar permanent magnets c with the pole pieces, e. g., a pair of such magnets with the pole pieces arranged at their ends, the ends of the magnets are engaged with slots in the pole pieces. Thus the ends of the magnets may be chamfered or slipped into dovetail recesses in the pole pieces. The magnets are held in position partly by the pole pieces and partly by the end pieces, no separate fastenings for the magnets, such as screws, being then required.

In some two pole machines fitted with upper and lower pole pieces, the laminations forming the lower pole piece may be shaped to provide also a foot or base for the machine. ()r a set of laminations may be cast with or otherwise secured to a solid metal base or foot.

hen it is not desired to attach the magnets by means of the pole pieces, a construction as shown in Figure 3 may be employed. In this example the pole pieces a are'constructed as above described, and the magnets e which are of curved form simply abut against the pole pieces and are held inposition by a metal strapf which embraces the magnets and is attached at its ends to the base of the machine.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a dynamo electric machine thecombination of separate opposed end members having recesses in the inner faces thereof, permanent magnets confined between said end members, laminated pole pieces located between the end members having openings extending from end to end thereof alining with said recesses, removable pins located in said openings and being of greater length than said pole pieces and projecting beyond the ends of each of the latter, each pin havtwo alined recesses in the opposed end members, and fastening means removed from the pole pieces and passing through the end members for securing the whole together.

2. In a dynamo electric machine, the combination of separate opposed end members having recesses in the innerfaces thereof, flat permanent magnets confined between the and members, laminated pole pieces located between the end members having recessed portions accommodating the pennanent magnets and preventing lateral displacementof the latter, said pole pieces also having an opening extending from end to end thereof alining with the recesses in the end members, removable pins located,

ERN ST ANSLEY WATSON. 

